Field of the Invention
This invention relates to a hydraulic control apparatus for controlling a flow of hydraulic oil which is supplied to a power transmission mechanism.
Description of the Related Art
Conventionally, as an apparatus of this type is known as one that is equipped with a first hydraulic pump and a second hydraulic pump and controls flow of pressure oil supplied to an automatic transmission from these hydraulic pumps. For example, Japanese Unexamined Patent Publication No. 2014-163457 (JP2014-163457A) teaches an apparatus equipped with a first hydraulic pump driven by an engine and a second hydraulic pump driven by an electric motor, which during vehicle travel supplies oil discharged from the first pump to a hydraulic actuator for driving pulleys of a continuously variable transmission and during stopping of the engine by idling stop control supplies oil discharged from the second hydraulic pump to the hydraulic actuator.
However, in the apparatus described in JP2014-163457A, when the automatic transmission (for example, its pulley drive unit) requires pressure oil of large flow rate during vehicle travel, this requirement must be met solely by oil discharged from the first hydraulic pump, so that the first hydraulic pump tends to be large.